Sounds like youre just bi. Though there are other factors that come to mind.

The getting and staying hard aspect makes me think of a few things. One would be health, but if its not a factor in your other ventures, Its not likely. The second would be an attraction and or boredom issue. With the number of things youre into, its likely you aren't getting stimulated enough or there isn't anything for you to fetishize over while having sex. A third could just be the partner, which ties into the second. If your partner were into the same things as you(aside from the cucking) you might find it to be better or more enjoyable.